A82 5-ASA & CHEMOPREVENTION IN IBD: A POPULATION-BASED ANALYSIS
Bibliographic record
Abstract
Inflammatory bowel disease (IBD), which includes ulcerative colitis (UC) and Crohn’s disease (CD), is a chronic, relapsing and remitting inflammatory disease of the gastrointestinal tract. Colorectal cancer (CRC) is a well-documented complication of IBD and is associated with IBD severity, extent and duration. Treatment with 5-aminosalicylic acid (5-ASA) reduces the risk of CRC in IBD. Our objective was to test the association of cumulative exposure to 5-ASA on CRC risk. A retrospective cohort study was performed using a population-based IBD cohort derived from administrative health data in Saskatchewan, Canada. Data were from 1979 to 2011. Exposure to 5-ASA and CRC diagnosis using ICD diagnoses during the study period were examined. CRC rates were compared between 5-ASA exposed/non-exposed groups using chi-square tests; exposure to 5-ASA was evaluated using survival analysis. To account for differences in 5-ASA exposure, propensity scores (PS) based on IBD duration, immunomodulator (IM) and anti-TNF exposure, number of endoscopies, and decade of IBD diagnosis were used to match non-exposed to exposed patients. In the propensity-matched cohorts, we controlled for gender, location (urban/sub-urban/rural), diagnosis and previous corticosteroid use. A dose response survival model was developed in an attempt to control for the duration of 5-ASA. We assumed a 5-ASA dose of 2000 mg/day, and subsequently marked subjects as being “off” treatment if they did not renew a prescription within 30 days of their last prescription. The Kaplan-Meier estimator was used to describe the time-to-event data and Cox proportional hazards regression models were used to test the association of exposure with CRC diagnosis; hazard ratios (HRs) and 95% confidence intervals (95% CIs) were reported. Analyses were stratified by type of IBD (UC, CD). A total of 8821 IBD patients were included in the study, of which 289 (3.3%) developed CRC. In the CRC-free group, 73.9% (n=6307) of patients had exposure to 5-ASA, whereas 61.9% (n=179) had exposure in the CRC group. In the PS-matched cohort, the HR was 2.56 for exposed versus non-exposed individuals (95% CI:[1.9, 3.5]). The risk of CRC diagnosis was higher in the UC sub-group (HR=3.54, 95% CI:[2.3, 5.5]) when compared to the CD population (1.73, 95% CI:[1.1, 2.6]), controlling for gender, location and decade of diagnosis. In our adjusted dose-response model using truncated 5-ASA dosing, the risk of CRC diagnosis was higher in the UC sub-group (HR=2.83, 95% CI:[1.6, 5.1]) when compared to CD (HR=2.17, 95% CI:[1.1, 4.2]). This population-based cohort study suggests a chemo-protective effect of 5-ASA exposure for CRC diagnosis amongst patients with IBD. A larger protective effect was observed amongst UC patients than CD patients. Further data are needed to elucidate the biologic mechanism of CRC reduction. None
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.003 | 0.004 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.006 |
| Bibliometrics | 0.002 | 0.003 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.005 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".